Underwing lights - P39/Boomerang

Thought I might have a pic of them in the collection of shots I took of a P-39 in a collection here in the states, but no joy.

If memory serves, the lights run red, green, and amber moving fore to aft. These were standard issue on the majority of American built aircraft, rather than a theater-specific modification. The lights were intended as an early form of "friend or foe" identification to reduce friendly fire incidents at night from other aircraft or AAA guns, not so much for communication with ground forces.

On the P-38J, the lights were wired to a control panel on the port side of the cockpit, which allowed the lights to be toggled on and off, as well as a switch which allowed the lights to be used to flash signals in Morse code. Specific orders on how the lights were to be used depended upon the units operating the aircraft. I think the RAF had a procedure in place which stated that the lights were only to be used at altitudes of less than 2000 feet in areas less than 50 miles from an airbase, while USAAF bombers frequently employed the lights for making adjustments to a formation of planes during take-offs and landings.

Ok folks, found a really good colour underwing shot of Matt Denning's Boomerang, so for anyone else considering building a Boomerang, the lights run red-yellow-green moving outwards from the aircraft centreline.